Ion implant systems for Silicon On Insulator (SOI) substrate processing are currently based upon the implantation of hydrogen and helium ions into a semiconductor substrate at the same depth range (Rp). Previously, H-implantation in Si marked the beginning of a new era in the electronic industry when it was first coupled with the direct wafer bonding technique. This coupled process is now generally referred to as an ion-cut process, or smart cut, because the ion implantation is used to sever a portion (layer) of a semiconductor wafer from a remaining portion of the semiconductor wafer.
Generally the separation process to produce a substrate for subsequent smart cut processing is produced by chemical interaction such as bond breaking and passivation and a physical interaction such as gas coalescence, pressure and fracture, of implanted hydrogen ions in a semiconductor substrate. Helium, which may be used to assist smart cut processing, is a noble gas and does not produce a chemical interaction in a silicon substrate as does hydrogen. However, helium does induce a physical interaction and in a more efficient manner than hydrogen.
In current practice He and H co-implantation creates a buried damage layer having a large number of fine voids which form a weakened region that can be used to delaminate a portion of the wafer during subsequent processing. This technique forms the basis of generating high quality SOI wafers that may be used for device fabrication. The technique has recently been extended for use with Ge and SiGe wafer processing as well as processing compound semiconductor wafers. In current technology for processing silicon wafers, a high current (HC) Hydrogen implanter may be employed to process wafers in which a high dose of implanting ions is used to process wafers. For example, the HC implanters may use a high mass resolution beam line components to implant both H+ and He+ at dose ˜1016 to ˜1017 ions/cm2, and at energies in the range of 20 to 100 KeV. This process is rather slow, expensive and requires very high concentrations of Hydrogen atoms.
In view of the above, it will be appreciated that there is a need to develop ion implantation technology to enhance ion introduction efficiency, to provide a low material cost and high implant productivity system for SOI processing.